1. Field of the Invention
The invention relates to a support column for underground mining and tunnel construction which is composed of a load-bearing outer shell and a core of a substance which is to be introduced in the flowable state and which is capable of hardening.
2. Description of the Related Art
Support columns are known and are described in DE-OS 28 47 906 and DE-OS 39 15 837. In practice, it has been found that it is frequently necessary, for rock-mechanical reasons, to mount columns with defined setting forces and to apply a load to the column. The above-mentioned columns or stays reach their full load-bearing capacity only after the substance which has been filled in has hardened. It is known from DE-OS 28 47 906 that a certain early load-bearing capacity can be achieved by providing an auxiliary stay which remains on the column until the substance in the column has hardened. DE-OS 39 15 837 describes a clamping possibility which is effected by means of a winding mechanism. In this case, the magnitude of the clamping forces is limited and cannot be adapted to the rock-mechanical requirements. In this construction, the complicated winding mechanism remains in the filled column and loses its function after the column has been filled. In systems which are not reusable, such a procedure is not economical.
The invention is based on the objective of developing a support column of the above-described type which makes it possible in an economical manner to obtain an immediate support force in accordance with the given rock-mechanical requirements before filling in and hardening of the substance and which maintains this support force even after the clamping device has been removed.
In accordance with the invention, this objective is met by providing an upper column component which is slidable out of a lower column component and is secured against sliding into the lower column component by means of a ring-shaped spring element which is secured relative to the upper column component, the lower column component, and a sectional ring, wherein the spring element is constructed in such a way that the pretensioned spring force permits sliding of the upper column component out of the lower column component and, after the support column has been clamped, the contour of the spring element bearing against the upper column is connected therewith in a positively engaging manner.
Advantageous embodiments are the subject matter of dependent claims.
Machine elements which prevent a longitudinal movement of parts which are inserted one into the other are generally known in the art. Such elements are, for example, resilient securing rings which prevent an axial displacement in one direction on smooth shafts or axles.
However, it is novel and inventive to equip support columns with such spring elements.
Additional details of the invention will be described in the following with the aid of schematically illustrated embodiments.